Development and differentiation of neural rosettes derived from human embryonic stem cells.

Neurons and glia are important targets of human embryonic stem cell research, promising a renewable source of these differentiated cells for biomedical research and regenerative medicine. Neurons and glia are derived in vivo from the neuroepithelium of the neural tube. Concomitant to development along the anterior to posterior axis, gradients of morphogens across the dorsal and ventral axis of the neural tube establish positional codes that generate distinct progenitor domains and ultimately specify subtype identity. The neural rosette is the developmental signature of neuroprogenitors in cultures of differentiating embryonic stem cells; rosettes are radial arrangements of columnar cells that express many of the proteins expressed in neuroepithelial cells in the neural tube. In addition to similar morphology, neuroprogenitors within neural rosettes differentiate into the main classes of progeny of neuroepithelial cells in vivo: neurons, oligodendrocytes, and astrocytes. Despite these similarities, important differences exist and the extent to which neural rosettes can model neurogenesis in vivo is not yet clear. Here, the authors review the recent studies on the development and differentiation of neural rosettes from human embryonic stem cells. The authors focus on efforts to generate motor neurons and oligodendrocytes in vitro as representative of the challenges to obtaining the progeny of a single progenitor domain with in vitro methods. Opportunities for further progress are discussed.